questions","basePath":"/gcse/computer-science/aqa/data-compression/questions","formulaUrl":null,"initialIndex":38,"initialQuestionWindow":[{"id":"a7484418-cd62-4496-83ba-fb3e31c3cfb2","revisionId":"78f0e830-4512-4301-8a0b-99342da47a02","questionNumber":null,"questionType":"LA","specification":"A Huffman tree has been created for the phrase 'DEEP BLUE'.\n\n![Huffman tree for DEEP BLUE](https://assets.mathsgenie.co.uk/aqa-qb/1a868ffc-5ce1-4bc8-8b30-83fe75d12a49.png)","difficulty":3,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"7db92424-029b-40d7-bc2d-4195119d4b7c","label":null,"content":"What is the correct binary encoding for the substring **BLED**?\n\n| Letter | Binary Encoding |\n| :--- | :--- |\n| B | |\n| L | |\n| E | |\n| D | |\n\nWrite your final full sequence below your table.","markscheme":"- Identifies at least 3 of the correct individual letter encodings: $B = 011$, $L = 100$, $E = 11$, $D = 000$ M1\n- Correctly joins the binary codes to form the complete sequence $01110011000$ A1","marks":2,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"aa7ccd65-3f93-474b-99ec-d6dba037ad0e","revisionId":"829b3c7e-4c09-48cf-8584-1cc930df20f2","questionNumber":null,"questionType":"LA","specification":"","difficulty":4,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"97554e90-9f62-445b-85e4-2b90a38167c2","label":null,"content":"A digital scanner reads a sequence of pixel values from a multi-colored calibration strip:\n\n`C M Y K C M Y K C M Y K`\n\n*(Where C = Cyan, M = Magenta, Y = Yellow, K = Black)*\n\nExplain why Run-Length Encoding (RLE) is not a suitable method for compressing this sequence.","markscheme":"- Identifies that there are no consecutive repeating colors or \"runs\" of identical values in the sequence M1\n- Explains that RLE requires storing a run-count alongside each individual color value (e.g., `1C 1M 1Y 1K...`), which doubles the data storage requirement (12 values become 24), causing data expansion rather than compression A1","marks":2,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"ad569b4c-758c-4976-ba61-30b02b3237a5","revisionId":"62216e29-210c-4c1b-9e4f-d74b1741b06e","questionNumber":null,"questionType":"LA","specification":"Figure 1 contains a Huffman tree used to encode text characters.\n\n![Figure 1: A Huffman tree representing characters H, E, A, R, and T.](https://assets.mathsgenie.co.uk/aqa-qb/e6798a22-c2f5-407b-901c-47084b0c98d4.png)\n\nFigure 1 was used to encode a string, resulting in the following bit pattern:\n\n`011011011100`","difficulty":4,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"29674a3f-8b4a-440d-8db2-2c4e406a9e21","label":null,"content":"State the string that this bit pattern represents.","markscheme":"- Shows a correct method of traversing the Huffman tree to decode at least two characters (e.g., identifying that $01$ represents 'E' and $10$ represents 'A') M1\n- Correctly identifies the complete decoded string as \"EARTH\" A1","marks":2,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_computer_science__aqa","summaries":[{"id":"01aceeda-575c-4ced-bc96-ba092de79c7e","difficultyBand":"medium","calculatorUse":null},{"id":"03fe5cea-6efd-45d9-aa60-75964ab4705a","difficultyBand":"easy","calculatorUse":null},{"id":"07d36a1a-5c14-476d-80ea-f2079e422bfb","difficultyBand":"easy","calculatorUse":null},{"id":"0ab264e5-e293-4736-91b6-fd500dfb6b02","difficultyBand":"easy","calculatorUse":null},{"id":"0fc37e4c-7cae-4c1a-9fb3-66f966107332","difficultyBand":"medium","calculatorUse":null},{"id":"1cb71686-bddf-4766-bac7-646e97cdb718","difficultyBand":"easy","calculatorUse":null},{"id":"1d080ea0-8d9f-41a4-

Data compression

Question 25

Data compression Questions

Data compression

Question 25

Data compression Questions